This is a 1.5-mile (2.4 km) combined out-and-back with two summit spurs from the layby on the western side of Thirlmere. The stored distance is the total walked experience: climb to Castle Crag, return to the forest track, take the spur to Raven Crag, then descend to the same access.
Start along the road, turn through the deer-fence gate, and follow the steep gravel path into the trees. Cross the forestry tracks and take the narrow path to the Castle Crag hillfort, then return to the forest road. The Raven Crag branch uses more steps and boardwalk before reaching the open top of the crag. Return by the same forest route and road.